Coordinated water environment mobile robots

ABSTRACT

A two-part, selectively dockable robotic system having counterbalanced stabilization during performance of an operation on an underwater target structure is provided. The robotic system includes a first underwater robotic vehicle that is sized and shaped to at least partially surround the underwater target structure. A second underwater robotic vehicle is sized and shaped to at least partially surround the underwater target structure and selectively dock with the first underwater robotic vehicle. The first and second robotic vehicles include complimentary docking mechanisms that permit the vehicles to selectively couple to each other with the underwater target structure disposed at least partially therebetween. One robot includes a tool that can act upon the target structure and the other robot includes a stabilization module that can act upon the target structure in an opposite manner in order to counterbalance the force of the tool.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to U.S.Provisional Application Ser. No. 62/397,175, filed Sep. 20, 2016, whichis hereby incorporated by reference as if set forth in its entiretyherein.

FIELD OF THE INVENTION

Systems, methods and devices for performing inspection and other taskson underwater assets including underwater pipelines and structures areprovided that include or utilize at least first and second robots thatare configured to cooperate with one another in support of an operationon a target pipeline or other structure.

BACKGROUND OF THE INVENTION

Underwater inspection operations can be a complicated task for a roboticsystem, especially when the task is performed while floating in water,for example, at a midpoint of the water column. Robotic manipulation ofan inspection tool, such as an inspection arm, can be difficult asreaction forces from the inspected surface can push a remotely operatedvehicle (“ROV”) backward and disturb its stability. Similarly,performing marine life cleaning on an underwater pipe or pipeline, e.g.,using a water jet, will create a strong push back making it difficult tostabilize the ROV.

Accordingly, there is a need to provide underwater vehicles that arestructurally configured and operationally controlled to solve thestability issues associated with reaction forces caused by operation oftools, for instance, a robotic arm or a cleaning system (by way ofexample, and not limitation, a spinning brush or a cavitation/waterjet). The present invention as described herein provides a solution tothis and other problems.

SUMMARY OF THE INVENTION

In one aspect of the invention, a two-part, selectively dockable roboticsystem providing counterbalanced stabilization during performance of anoperation on an underwater target structure is provided. The roboticsystem includes a first underwater robotic vehicle that is sized andshaped to at least partially surround the underwater target structure. Asecond underwater robotic vehicle that is sized and shaped to at leastpartially surround the underwater target structure is also provided. Thesecond underwater robotic vehicle can be at least partially orientatedin a position opposite the first underwater robotic vehicle.Complimentary docking mechanisms are supported by the first and secondunderwater robotic vehicles and arranged so the first and secondunderwater robotic vehicles can selectively couple to each other withthe underwater target structure disposed at least partially between thefirst and second underwater robotic vehicles. A tool is provided thatexerts a first force against the underwater target structure in a firstdirection. The tool can be supported by one of the first and secondunderwater robotic vehicles. A stabilization module is provided thatexerts a second force against the underwater target structure in asecond direction to at least partially counteract the first force. Thestabilization module can be supported by one of the first and secondunderwater robotic vehicles.

According to a further aspect, the tool is a cleaning tool.

According to a still further aspect, the tool is a robotic arm.

According to another aspect, which can be combined in an embodimentconstructed in accordance with one or more of the foregoing aspects, thestabilization module is a contact roller.

According to a further aspect, the stabilization module includes aninspection sensor.

According to a still further aspect, which can be combined in anembodiment constructed in accordance with one or more of the foregoingaspects, the docking mechanisms include a hook/protrusion and areceptacle, wherein the receptacle is sized and shaped to receive eitherthe hook or the protrusion, as may be included in a particularembodiment.

According to a further aspect, which can be combined in an embodimentconstructed in accordance with one or more of the foregoing aspects, thedocking mechanisms include a latch and a protrusion, wherein the latchis operable to change positions to engage and disengage the protrusion.

According to a still further aspect, which can be combined in anembodiment constructed in accordance with one or more of the foregoingaspects, the docking mechanisms include moveable magnets that areoperable to change pole orientations in order to engage and disengagewith each other.

According to a further aspect, a method for performing a stabilizedoperation on an underwater target structure is provided. The methodincludes the steps of providing a two-part robotic system. The roboticsystem includes a first underwater robotic vehicle that is sized andshaped to at least partially surround the underwater target structure. Asecond underwater robotic vehicle that is sized and shaped to at leastpartially surround the underwater target structure is also provided.Complimentary docking mechanisms are supported by the first and secondunderwater robotic vehicles and arranged so the first and secondunderwater robotic vehicles can selectively couple to each other withthe underwater target structure disposed at least partially between thefirst and second underwater robotic vehicles. A tool is provided thatcan be supported by one of the first and second underwater roboticvehicles. A stabilization module is provided that can be supported byone of the first and second underwater robotic vehicles. The methodincludes the step of coupling the first and second underwater roboticvehicles to each other with the underwater target structure disposed atleast partially between the first and second underwater roboticvehicles. The tool is operated such that it exerts a first force againstthe underwater target structure in a first direction. The stabilizationmodule is operated such that it exerts a second force against theunderwater target structure in a second direction to at least partiallycounteract the first force.

According to a further aspect of the method, the tool is a cleaningtool.

According to a still further aspect of the method, the tool is a roboticarm.

According to another aspect of the method, which can be combined in anembodiment in accordance with one or more of the foregoing aspects, thestabilization module is a contact roller.

According to a further aspect of the method, the stabilization moduleincludes an inspection sensor.

According to a still further aspect of the method, which can be combinedin an embodiment in accordance with one or more of the foregoingaspects, the docking mechanisms include a hook/protrusion and areceptacle, wherein the receptacle is sized and shaped to receive eitherthe hook or the protrusion, as may be included in a particularembodiment.

According to a further aspect of the method, which can be combined in anembodiment in accordance with one or more of the foregoing aspects, thedocking mechanisms include a latch and a protrusion, wherein the latchis operable to change positions to engage and disengage the protrusion.

According to a still further aspect of the method, which can be combinedin an embodiment in accordance with one or more of the foregoingaspects, the docking mechanisms include moveable magnets that areoperable to change pole orientations in order to engage and disengagewith each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates coordinated water environment mobile robots inaccordance with one embodiment of the present invention;

FIG. 1A is a schematic illustration of coordinated water environmentmobile robots in accordance with an embodiment of the present invention

FIGS. 2A-2B illustrate a docking mechanism of coordinated waterenvironment mobile robots in accordance with another embodiment of thepresent invention;

FIG. 3 illustrates a docking mechanism of coordinated water environmentmobile robots in accordance with another embodiment of the presentinvention; and

FIGS. 4A-4B illustrate a docking mechanism of coordinated waterenvironment mobile robots in accordance with another embodiment of thepresent invention.

DETAILED DESCRIPTION CERTAIN OF EMBODIMENTS OF THE INVENTION

Referring to FIG. 1, a two part, selectively dockable robotic system 10is provided. The robotic system 10 provides counterbalancedstabilization during performance of an operation (e.g., inspection,testing, cleaning, maintenance, construction, and repair) on anunderwater target structure (e.g., pipe, cable, rig structure). Therobotic system 10 includes first and second underwater robots 100, 200.The first and second underwater robots 100, 200 are controlled by acontroller which is configured to coordinate their movements so thatthey cooperate and together improve the efficiency of various underwatertasks, as discussed in more detail below.

The first underwater robot 100 includes various thrusters 102 formaneuvering the robot 100 into position with respect to the targetstructure T. Once the robot 100 is in position, the thrusters 102 can beused to help maintain the position of the robot 100 and alsotranslationally move the robot 100 along the target structure T and/orrotationally move the robot 100 around the target structure T as therobot performs tasks. The thrusters 102 can be aligned or otherwiserotated to align along different axes of the robot (e.g., x, y, and zaxis) so that the robot can move in the three-dimensions in theunderwater environment.

In FIG. 1, the target structure T is an exemplary underwater pipe. Otherstructures, such as cables, supports columns, tanks, anchoring chains,and other various marine infrastructure can be operated upon by therobot system 10; an underwater pipe is merely illustrated as an exampletarget T.

The first robot 100 includes a tool 104 that is used to perform workupon the target structure T. For example, as shown in FIG. 1, the tool104 can be a waterjet capable of expelling water at a rate of speedsufficient to dislodge bio-growth and other matter from the target T.Other tools, such as robotic arms, cleaning brushes, sensors, cameras,non-destructive inspection and testing equipment, sand blasters,welders, or other tools suitable for performing underwater inspection,testing, maintenance, cleaning, repair, or construction can also beused.

The first underwater robot 100 can have a hull structure 106 that issized and shaped to at least partially surround the underwater structureT. For example, the underwater robot 100 can have a U-shaped hull thatis sized and shaped for partially surrounding the structure T. As shownin FIG. 1, a U-shape hull is particularly suited for partiallysurrounding cylindrical objects, such as pipes. The hull 106 can haveother sizes and shapes that can be designed to complement the targetstructure T. The hull 106 can include arms 108 and 110 that extendoutwardly to at least partially encompass the target T and extendtowards the second robot 200 and support first docking mechanisms 112 tofacilitate docking between the two robots 100, 200, as discussed in moredetail below.

The second underwater robot 200 can be similar to the first robot 100 inmany respects. The second robot 200 can include a set of thrusters 202for maneuvering into position and traversing the target structure T. Thethrusters 202 can be aligned along different axes of the robot (e.g., x,y, and z axis) so that the robot can move in the three-dimensions in theunderwater environment. The second robot 200 can have a hull 206 thathas a similar size and shape to hull 106 of the first robot 100,including similar arms 208 and 210. Similarly, second docking mechanisms212 can be supported by arms 208 and 210.

The second underwater robot 200 includes a stabilization module 204. Asshown in FIG. 1, the stabilization module can comprise a roller that isarranged to contact the target structure T. Other devices, such asslides, bearings, skids, rollers, or other similar devices can be usedto contact and apply a force against the target structure T. Thestabilization module 204 provides a counterbalancing and stabilizationforce to the first robot 100 and the tool 104, as discussed in moredetail below. Because the stabilization module 204 is in contact withthe target structure T during operation of the tool 104, thestabilization module 204 can also include a sensor or othernon-destructive testing equipment (e.g., camera, ultrasonic transducer,capacitive senor) that can inspect the condition of the target structureT. Accordingly, as the tool 104 performs operations on the targetstructure T (e.g., cleaning), the stabilization module 204 can provide acounterbalancing force and also can inspect the structure to confirmthat the tool 104 has performed its operation satisfactorily or tosignal when the intended operation performed by the tool is completesuch that the robots 100, 200 can be removed from the target T or movedto a new location about a different target surface.

Cooperating component parts can be provided on the first and secondunderwater robots 100, 200 to provide a docking connector D that permitsthe robots to selectively couple with one another. The docking connectorcan include a first docking mechanism 112 supported by the first robot100 and a second docking mechanism 212 supported by the second robot200. The first docking mechanisms 112 are supported by arms 108 and 110while and the second docking mechanism are supported by arms 208 and210.

Turning briefly to FIG. 1A, a schematic representation of thearrangement of FIG. 1 illustrates the first and second underwater robots100, 200 coupled together in surrounding relation to the underwatertarget T. The arms 108, 110, 208, and 210 can also be configured toextend in length (e.g., telescopically) or be in the form of ropes,chains, or cable, as illustrated schematically in FIG. 1A. Accordingly,the length of the arms can be adjusted so that first and second robots100, 200 can dock together and accommodate target structures T ofvarious sizes and shapes. As shown in FIG. 1A, the first dockingmechanism 112 can be a receptacle, such as a ring, that is sized andshaped to receive the second docking mechanism 212, which can comprise ahook-shaped protrusion. The second docking mechanism 212 can be insertedinto and retained by the first docking mechanism 112 to couple the firstand second robots 100, 200 together. Other docking mechanismarrangements can be used, such as the docking mechanisms shown in FIGS.2-4, which are discussed in more detail below. The thrusters 102, 202,and stabilization module 204 can be operated as described above.

When the first and second robots are coupled together via the dockingmechanism they can at least partially surround the underwater targetstructure T. For example, the first and second robots 100, 200 can besized and shaped to cross-sectionally surround the target structure Twith the target structure T disposed between the robots, as shown inFIG. 1. In this configuration, the tool 104 is positioned for operationupon the target structure T and the stabilization mechanism 204 ispositioned to provide a counterbalancing force to the forces exerted bythe tool 104. As the tool 104 performs work upon the target structure(e.g., water jet cleaning), a force is exerted upon the target structureand an equal and opposite force is experienced by the first robot. Thisopposite reaction force can cause the first robot 100 to be pushed awayfrom the target structure T. Without proper counteracting forces, thefirst robot 100 moves out of position and away from the target structureT and is either not be able to perform its task or not able to performthe task efficiently once displaced. The stabilization module 204 of thesecond robot 200 counteracts the reaction force experienced by the firstrobot 100. Thus, in accordance with the invention, because the first andsecond robots 100, 200 are coupled together, the first robot 100 is heldin place as it works on the target structure by the second robot 200. Asthe tool 104 is operated it applies a first force against the targetstructure T and the stabilization module provides a second equal andopposite force that counteract the first force. Since the first andsecond robots 100, 200 are coupled together via the docking mechanisms,the net force experienced by the first and second robots 100, 200 iszero. The net zero force allows the robots to remain in a stableposition with respect to the target structure T. Accordingly, the firstand second robots and the active tool and the stabilization module workin concert to provide a stable working platform so that variousoperations can be performed on the target structure.

As an example, tool 104 can be a waterjet that blasts water at highpressure against the target structure T, which can be a pipe, as shownin FIG. 1. The waterjet can be directed onto the outer surface of thepipe to remove various debris, such as marine fouling and/or corrosionfrom the pipe surface. As the waterjet blasts against the surface of thepipe in one direction, the first robot experiences forces pushing itaway from the pipe. Accordingly, the stabilization module 204, which cancomprise a roller, contacts the other side of the pipe. The force ofcontact between the roller and the pipe surface is equal and opposite.These two forces are transmitted through the docking mechanism couplingthe first and second robots 100, 200 together and cancel each other out.Accordingly, the robots remain stable with respect to the pipe and thecleaning operation can be performed efficiently in a controlled, stablemanner.

In addition to being physically coupled together via the dockingmechanisms, the first and second robots 100, 200 can also be coupledtogether so that control signals and other signals can be transmittedbetween the first and second robots. The robots can be connected via anelectrical connection, which can be a part of the docking mechanism,and/or they can be connected via wireless communication modules (e.g.,using Bluetooth®, near field communications, IEEE 802.11, or anothercommunication protocol). Such a connection allows the robots to operatetogether in a coordinated-control fashion. For example, when the firstrobot moves along the target surface using its thrusters, it can providecontrol signals to the second robot to operate its thrusters in acomplementary manner so that the first and second robots move in concerttogether. Accordingly, as the first robot moves along the targetstructure the second robot will follow and continue to provide thecounterbalancing stabilization force required to maintain the robots indesired position with respect to the target structure.

According to one arrangement, communication can be established betweenthe surface (e.g., a surface based control station, communication relayvehicle, or support vessel) and the first and second robots. Thecommunication can be established using tethers (e.g., between thesurface and the first and second robots) or a wireless technology (suchas acoustics, laser, visible light, RF). Alternatively, a parent-childconfiguration could be used where a direct connection is establishedbetween the surface and a “main robot” (e.g. the first robot 100) usinga tether, while the other “support robot” (e.g., the second robot 200)is then tethered to the main robot. This configuration reduces thenumber of tethers running to the surface. The connection between the tworobots could also be accomplished using a short range wirelesstechnology.

In one control scheme, the first and second robots can be independentlycontrolled until they dock together. After docking is completed, thefirst and second robots can be configured to be remotely controlled asone unit to traverse the underwater target structure longitudinally orcircumferentially.

Before docking, controllers on either robot can receive separatecommands from the operator (e.g. joysticks) in order to actuate thecorrect thrusters to achieve the motion desired by the operator. Toachieve the docking maneuver, one of the first and second robots (e.g.,support robot) can be remotely controlled to rest against the underwatertarget structure (e.g., pipe) and optionally use sensors toautomatically hold depth, orientation and/or position (using for examplepressure sensor and compass). The operator and/or automatic controllerprovided by an onboard processor can also provide additional thrustforce against the target structure surface to counteract recoil duringdocking.

The other of the first and second robots (e.g., main robot) is remotelycontrolled by the operator to maneuver it within vicinity of the supportvehicle to initiate docking. Docking can then be performed manually bythe operator or autonomously by the onboard controller on the mainvehicle using onboard cameras or sonars or any suitable sensor to guidethe docking maneuver. The controllers on both robots can alsocommunicate with each in order to perform automatic corrections andthereby aid in the docking. The two robots can be remotely controlled inthis manner at the same time or one after the other.

Once docking is completed, the operator can control the first and secondrobots as one unit in such way that the individual controllersassociated with each of the first and second robots can exchange signalsto determine which thrusters on the combined vehicle need to be actuatedto achieve the desire motion by the operator including translation androtation in any direction. Moreover, the controllers could also unlockextra degrees of freedom by using new combinations of thruster on bothvehicles to achieve certain motions not possible by one vehicle due torestrictions on available thrusters.

Moreover, while performing a task, such as cleaning or inspection thecontrollers could automatically hold position by using the combinedthrusters to correct for any longitudinal, circumferential or otherdisplacements.

Once the task is completed, undocking can be performed. For example, thecontrollers can actuate their respective thrusters in oppositedirections to undock. The controllers can also operate the dockingmechanism to cause the first and second robotic vehicles to undock fromeach other. Independent manual control is regained over both the firstand second robots after undocking is completed.

FIGS. 2A-2B show the first docking mechanism 112 of the first robot 100and the second docking mechanism 212 of the second robot 200 accordingto a particular embodiment. The first docking mechanism 112 includes aprotrusion that has a conically-shaped, flared portion 150 and anelongated post 152. The second docking mechanism 212 includes areceptacle that has a conically-shaped, flared portion 250 and anelongated hole 252 that are sized and shaped to receive the flaredportion 150 and elongated portion 152 of the first docking mechanism112, respectively, as shown in FIG. 2B. When the first docking mechanism112 is received by the second docking mechanism 212, the first andsecond robots 100, 200 are coupled together (FIG. 2B).

FIG. 3 shows the first docking mechanism 112 of the first robot 100 andthe second docking mechanism 212 of the second robot 200 according to aparticular embodiment. The first docking mechanism 112 includes awedge-shaped receptacle 300 that is sized and shaped to receive thewedge-shaped protrusion 302 of the second docking mechanism 212. Thefirst docking mechanism 112 includes two mechanically operable latches304. The latches 304 include a sloping face 306 that is sized and shapedto compliment a forward edge 308 of the protrusion 302. As theprotrusion 302 moves toward the receptacle 300 for docking, thecomplimentary surface 306 and 308 allow the parts to slide past eachother more efficiently. The latches 304 include a generally flat surface310 on a side opposite the sloping face 306. The protrusion 302 includesa shoulder 312 that as sized and shaped to receive the latches 304 withthe flat surface 310 disposed adjacent the shoulder 312 when the firstand second docking mechanisms 112, 212 are coupled.

The latches 304 are each supported by a pivot 314 and are connected forrotation about the pivot 314. An actuator 316, such as a solenoid, isconnected to an arm 318 and is configured to extend and retract the arm318 upon actuation of the actuator 316. The arm 318 is positioned withrespect to the latch 304 to contact the latch when the actuator 316 isactuated into an extended position. The arm 318 includes a spring 320that is connected to the latch 304 such that spring 320 exerts a pullingforce upon the latch 304 upon retraction of the actuator 316. Since thelatch is connected to the pivot 314, the actuation of the actuator 316cause the latch 304 to rotate in both directions about the pivot 314.Accordingly, the actuator 316 can be actuated to rotate the latch 304into a position to facilitate docking, rotated and maintained inposition to maintain the robots in a docked configuration, and thenrotated in an opposite direction to move the latch 304 so that therobots can decouple.

FIGS. 4A-4B illustrate the first docking mechanism 112 of the firstrobot 100 and the second docking mechanism 212 of the second robot 200according to a particular embodiment. The docking mechanisms 112, 212each include a motorized magnet 400, 402, respectively. The motorizedmagnets 400, 402 include a magnet having north and south poles that canbe rotated so that the orientation of the north and south poles can bechanged. Flux concentrators 404 are provided adjacent the motorizedmagnets 400, 402 so that the magnetic force of the magnet can beconcentrated and directed toward opposing surfaces of the dockingmechanisms 112, 212. The flux concentrators 404 can include recesses 406that are sized and shaped to compliment the motorized magnets 400, 402so that the space between the flux concentrators 400 and the motorizedmagnets 400, 402 can be minimized, thereby increasing the effectivenessof the flux concentrators.

As shown in FIG. 4A, the motorized magnets 400, 402 are oriented so thatthe poles are directed towards the flux concentrators 404. Motorizedmagnet 400 is oriented with its poles opposite the poles of motorizedmagnet 402. Accordingly, in this configuration, the docking mechanisms112 and 212 experience an attractive magnetic force that facilitates andmaintains coupling between the first and second robots 100, 200. Oncedocking is complete, the motorized magnets 400, 402 are rotated so thatthe poles are not directed toward the flux concentrators 404 andopposite poles are directed toward each other, as shown in FIG. 4B.Accordingly, no net magnetic force is directed through the fluxconcentrators 404 and the opposing poles of the magnets facilitatedecoupling of the first and second robots 100, 200. Similarly, themotorized magnets 400, 402 can be rotated with the poles directedtowards the flux concentrators 404 with the same pole orientation,causing a repulsive, decoupling force to be directed through the fluxconcentrators 404.

While the robots 100, 200 have been described as each having a tool 104and a stabilization module 204, respectively, the tool 104 can beassociated with the robot 100 and the stabilization module can beassociated with the robot 200, as the robots described herein areotherwise the same, save for having complementary docking connector Dfeatures. As an alternative, the tools, stabilization module, and/ordocking connector features can be supported one or the other of thefirst and second robots. Further, the first robot can be the “mainrobot” and the second robot can be the “support robot” and vise-a-versa.In an alternative embodiment, each of the robots 100, 200 can beprovided with both a tool and a stabilization module, substantially asdescribed above in connection with FIG. 1, in order to enable operationson either side of the target T with less rotation of the robots aroundthe target. As will be appreciated, the particular tool andstabilization module construction included with a particular robot 100,200 can be the same as included on the other robot, or different. Byproviding different tools on each of the robots 100, 200, a greaterrange of operations can be performed while the robots are underwater. Incertain embodiments, the robots 100, 200 can include a tether and/or therobots can be docked with each other with a rope or chain. As the robotsperform operation (cleaning and/or inspection) on the underwater targetstructure (e.g., helical sweep cleaning/inspection pattern) thetether/rope can wrap around the target structure. Once the operation iscomplete, the robots can perform a reverse maneuver that unwraps thetether/rope while also performing a second operation (cleaning and/orinspection).

It should be understood that like numerals in the drawings representlike elements through the several figures, and that not all componentsand/or steps described and illustrated with reference to the figures arerequired for all embodiments or arrangements. It should also beunderstood that the embodiments, implementations, and/or arrangements ofthe systems and methods disclosed herein can be incorporated as asoftware algorithm, application, program, module, or code residing inhardware, firmware and/or on a computer useable medium (includingsoftware modules and browser plug-ins) that can be executed in aprocessor of a computer system or a computing device to configure theprocessor and/or other elements to perform the functions and/oroperations described herein. It should be appreciated that according toat least one embodiment, one or more computer programs, modules, and/orapplications that when executed perform methods of the presentdisclosure need not reside on a single computer or processor, but can bedistributed in a modular fashion amongst a number of different computersor processors to implement various aspects of the systems and methodsdisclosed herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising”, when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

It should be noted that use of ordinal terms such as “first,” “second,”“third,” etc., in the claims to modify a claim element does not byitself connote any priority, precedence, or order of one claim elementover another or the temporal order in which acts of a method areperformed, but are used merely as labels to distinguish one claimelement having a certain name from another element having a same name(but for use of the ordinal term) to distinguish the claim elements.

Also, the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having,” “containing,” “involving,” andvariations thereof herein, is meant to encompass the items listedthereafter and equivalents thereof as well as additional items.

The subject matter described above is provided by way of illustrationonly and should not be construed as limiting. Various modifications andchanges can be made to the subject matter described herein withoutfollowing the example embodiments and applications illustrated anddescribed, and without departing from the true spirit and scope of thepresent invention, which is set forth in the following claims.

Notably, the figures and examples above are not meant to limit the scopeof the present application to a single implementation, as otherimplementations are possible by way of interchange of some or all of thedescribed or illustrated elements. Moreover, where certain elements ofthe present application can be partially or fully implemented usingknown components, only those portions of such known components that arenecessary for an understanding of the present application are described,and detailed descriptions of other portions of such known components areomitted so as not to obscure the application. In the presentspecification, an implementation showing a singular component should notnecessarily be limited to other implementations including a plurality ofthe same component, and vice-versa, unless explicitly stated otherwiseherein. Moreover, applicants do not intend for any term in thespecification or claims to be ascribed an uncommon or special meaningunless explicitly set forth as such. Further, the present applicationencompasses present and future known equivalents to the known componentsreferred to herein by way of illustration.

The foregoing description of the specific implementations will so fullyreveal the general nature of the application that others can, byapplying knowledge within the skill of the relevant art(s) (includingthe contents of the documents cited and incorporated by referenceherein), readily modify and/or adapt for various applications suchspecific implementations, without undue experimentation, withoutdeparting from the general concept of the present application. Suchadaptations and modifications are therefore intended to be within themeaning and range of equivalents of the disclosed implementations, basedon the teaching and guidance presented herein. It is to be understoodthat the phraseology or terminology herein is for the purpose ofdescription and not of limitation, such that the terminology orphraseology of the present specification is to be interpreted by theskilled artisan in light of the teachings and guidance presented herein,in combination with the knowledge of one skilled in the relevant art(s).It is to be understood that dimensions discussed or shown are drawingsare shown accordingly to one example and other dimensions can be usedwithout departing from the invention.

While various implementations of the present application have beendescribed above, it should be understood that they have been presentedby way of example, and not limitation. It would be apparent to oneskilled in the relevant art(s) that various changes in form and detailcould be made therein without departing from the spirit and scope of theapplication. Thus, the present application should not be limited by anyof the above-described example implementations.

What is claimed:
 1. A two-part, selectively dockable robotic systemproviding counterbalanced stabilization during performance of anoperation on an underwater target structure, comprising: a firstunderwater robotic vehicle sized and shaped to at least partiallysurround the underwater target structure; a second underwater roboticvehicle sized and shaped to at least partially surround the underwatertarget structure and be at least partially orientated in a positionopposite the first underwater robotic vehicle; complementary dockingmechanisms supported by the first and second underwater robotic vehiclesand arranged so the first and second underwater robotic vehicles canselectively couple to each other with the underwater target structuredisposed at least partially between the first and second underwaterrobotic vehicles; a tool that exerts a first force against theunderwater target structure in a first direction, the tool beingsupported by one of the first and second underwater robotic vehicles;and a stabilization module that exerts a second force against theunderwater target structure in a second direction to at least partiallycounteract the first force, the stabilization module being supported byone of the first and second underwater robotic vehicles.
 2. A two-part,selectively dockable robotic system according to claim 1, wherein thetool is a cleaning tool.
 3. A two-part, selectively dockable roboticsystem according to claim 1, wherein the tool is a robotic arm.
 4. Atwo-part, selectively dockable robotic system according to claim 1,wherein the stabilization module is a contact roller.
 5. A two-part,selectively dockable robotic system according to claim 1, wherein thestabilization module includes an inspection sensor.
 6. A two-part,selectively dockable robotic system according to claim 1, wherein thedocking mechanisms include a hook and a receptacle, wherein thereceptacle is sized and shaped to receive the hook.
 7. A two-part,selectively dockable robotic system according to claim 1, wherein thedocking mechanisms include a protrusion and a receptacle, wherein thereceptacle is sized and shaped to receive the protrusion.
 8. A two-part,selectively dockable robotic system according to claim 1, wherein thedocking mechanisms include a latch and a protrusion, wherein the latchis operable to change positions to engage and disengage the protrusion.9. A two-part, selectively dockable robotic system according to claim 1,wherein the docking mechanisms include moveable magnets that areoperable to change pole orientations in order to engage and disengagewith each other.
 10. A method for performing a stabilized operation onan underwater target structure, comprising the steps of: providing atwo-part robotic system, comprising: a first underwater robotic vehicle;a second underwater robotic vehicle; complementary docking mechanismssupported by the first and second underwater robotic vehicles andarranged so the first and second underwater robotic vehicles canselectively couple to each other with the underwater target structuredisposed at least partially between the first and second underwaterrobotic vehicles; a tool, the tool being supported by one of the firstand second underwater robotic vehicles; and a stabilization module, thestabilization module being supported by one of the first and secondunderwater robotic vehicles; coupling the first and second underwaterrobotic vehicles to each other with the underwater target structuredisposed at least partially between the first and second underwaterrobotic vehicles; operating the tool such that it exerts a first forceagainst the underwater target structure in a first direction; andoperating the stabilization module such that it exerts a second forceagainst the underwater target structure in a second direction to atleast partially counteract the first force.
 11. The method of claim 10,wherein the tool is a cleaning tool.
 12. The method of claim 10, whereinthe tool is a robotic arm.
 13. The method of claim 10, wherein thestabilization module is a contact roller.
 14. The method of claim 10,wherein the stabilization module includes an inspection sensor.
 15. Themethod of claim 10, wherein the docking mechanisms include a hook and areceptacle, wherein the receptacle is sized and shaped to receive thehook.
 16. The method of claim 10, wherein the docking mechanisms includea protrusion and a receptacle, wherein the receptacle is sized andshaped to receive the protrusion.
 17. The method of claim 10, whereinthe docking mechanisms include a latch and a protrusion, wherein thelatch is operable to change positions to engage and disengage theprotrusion.
 18. The method of claim 10, wherein the docking mechanismsinclude moveable magnets that are operable to change pole orientationsin order to engage and disengage with each other.